3/14/18

Today’s Class Growing Growing Healthy Soil: Healthy Soil 1. Soil physical properties: texture and structure 2. Improving physical & biological properties with organic matter 2018 3. Soil chemistry: pH and nutrients Extension Gardener Short Course 4. Soil testing Class 2

What do healthy soils provide plants?

• Water & Nutrients + • Want right amount and Healthy soil is the foundation of healthy constant supply of plant growth both + • How do plants get water and nutrients from soils? Soil controls fate of water and nutrients

ROOTS! What do healthy soils provide plants?

• Water and Nutrients • Air! Roots have to have it! • Soils that are easy to dig have plenty of air • Microbes • Beneficial microbes help roots absorb nutrients and suppress soil diseases Root health and plant growth is directly • Microbes need water, nutrients and air reliant on soil conditions

1 3/14/18

What do healthy soils provide plants? Top growth directly proportional to root growth! Space/Depth • Roots need space to grow both deep and wide • Roots grow where there is air, water and nutrients • Want these to extend deep into the soil profile – ideally: – At least 8” for turf, annuals and vegetables – At least 2’ for shrubs and small trees – 3’ or more for large trees

Soil Physical Soil Particles Properties Sand Improve before you plant! • Feels gritty, largest particle size • Particles • Cannot hold nutrients • Color Silt • Texture • Feels floury, medium particle size • Structure • Pure silt rare • Pores Clay • Compaction • Feels smooth, can mold, “ribbons” • Depth • Smallest particle size, holds Clay soils “ribbon” nutrients well You can’t fix it with fertilizer!!! when mashed

Soil Color

Red-orange • Due to Iron oxidation • Indicates good internal drainage Pale yellow, light gray • Poorly drained Darker colors, brown/gray hues • Organic matter darkens soils • Humus – what’s left when O.M. completely decomposed

Top = rust Bottom = humus

2 3/14/18

Mottled Soil Soil Texture Mottled grey and orange or yellow • Relative results from amounts of sand, seasonally high silt and clay in soil water table • Mixture of 2 or Orange due to more = loam oxidized iron • Unrealistic to (rust) – Iron change soil cannot oxidize if texture low oxygen

Piedmont Clay Implications of Texture • Water infiltration • Water holding capacity • Drainage • Aeration • Workability

Ultimate product of continuous weathering of minerals in a humid, temperate climate

Coastal Plain Soils Never work/dig wet clay!

TOO WET! Smearing/Glazing

3 3/14/18

Coastal Plain Soils Drainage

• Infiltration = surface drainage into the soil • Percolation = internal drainage through the soil profile

— Color as an indicator of drainage. The soil on the left is the Cecil series, a well-drained mineral soil typical of the NC piedmont. The soil on the right is the Coxville series, a mineral soil found in the NC coastal plain.

Where is water coming from? If excess, can it be re-directed? Measuring Drainage

– Dig 12” hole – Fill with water – Measure how long takes water to drain away • Less than an hour = excessive drainage • Less than 12 hours = good drainage • Over 24 hours = poor drainage

Soil Depth Shallow Soils • Poor growth • Want good rooting environment to extend deep into soil profile – Due to shallow root systems – growth of plant above ground • Enables drainage and deep root growth directly proportionate to size of root system • Healthy soils = 12”+ deep • Uprooting in wind • Common problems: – Trees with shallow root • Compaction systems are much more likely • Rock to uproot in high winds – If soils less than 3’ deep do not • High water table plant large maturing trees • Low pH, low air content (over 30’)

4 3/14/18

High Water Table Assessing Soil • Water table found within 12” of soil surface in some areas Depth • Highest in late winter/spring • Roots cannot grow into Dig a hole! • Dig until you reach water, saturated soil (no air) rock, compacted layer, or • If seasonal high water table get tired! (spring only), roots grow deeper in summer and fall and are killed back each winter/spring

Perched Water Table Perched Water Table • Occurs when soil layers of two different textures meet • Water will not freely move from one texture to another until first layer becomes Water saturated saturated top layer before moving into lower layer of different texture

Adding gravel to containers does not increase drainage! Make Your Bed!

• When amending soils, amend at least 10 sq. ft. area rather than planting hole • NEVER layer soils!

Source: https://secure.clematisqueen.com/content/do-not-add-gravel- your-containers Amend whole bed, not just planting hole!

5 3/14/18

Depth Raised Beds • Cultivate deep • Into clay • Mix in aged organic matter/compost

• Build up Trex – recycled plastic $$ • Above existing soil level • Ideally at least 12”, deeper for trees • Raised beds or berms • Fill with soil/compost mix • Don’t plant large maturing Treated or Concrete blocks trees (over 30’) in shallow untreated soils boards

Soil Pores Soil Structure Water

• Grouping of individual particles into clumps, aka aggregates • Creates pores • Allows water to move through soil and provides space for air

Compare Large Pores • Hold air • Let water into soil, allow drainage Small Pores • Light • Heavy • More air space • Hold water Ideal Volume: • Dense – less air • Readily absorbs • Water available to plants 20-30% large pores • Slowly absorbs water water 20-30% small pores • Holds water • Drains water

6 3/14/18

The Problem with Clay: Compare Compaction

Which is your soil more like? • Tiny particles – easily compacted • All small particles – hold water • Lack of large particles – low infiltration, drainage impeded

Every yard was a construction site at Compaction some point in the past! • If it is difficult for you to dig, it is difficult for roots to grow! • Causes: heavy equipment, constant foot traffic • Compaction causes poor surface drainage – encourages growth of moss, as do shade and acid soil

Moss is a symptom of compaction

Compaction Symptoms: Lichen

7 3/14/18

Surface Rooting Root Rot, Poor Growth

Turf fails to establish, Roots grow where there is air, low vigor Leyland cypress that died water and nutrients! from drowning

Turning a Brick Factors Affecting into a Sponge Structure

• Unrealistic to change • Wetting and drying texture = never add • Freezing and thawing sand!!! • Physical activity of roots • Want to improve structure • Animals • Organic matter binds soil • Soil tillage particles into aggregates = • Decaying organic matter improves structure

A pickaxe is NOT a planting tool! Earthworms improve soil structure over time

Organic Matter Increase Good Microbes • Improves number and distribution of large and small pores — Microscopic organisms • Increases infiltration bacteria, fungi, nematodes • Improves drainage Help plants grow better • Increases water holding capacity = Suppress diseases one of best defenses against — Thrive where plants thrive, in soils drought! that are • Also increases nutrient holding Consistently moist, not too wet capacity, adds nutrients and supports Rich in nutrients with moderate pH beneficial microbes! Have lots of organic matter

8 3/14/18

Organic Matter & Compost

• Available to buy – In bulk from mulch dealers In bags from garden centers • No need to seek out special types (eg. Mushroom compost)

Compost is available from most places that sell mulch.

Compost: Organic Matter Make Your Own — üGround pine bark – sold as pine or pine bark soil conditioner • A great way to recycle yard — ü Rotted leaves (leaf mold) – debris and vegetable scraps! pile them up and let them rot 2-3 • Two methods: years • Active = turn regularly — ü Aged manure – at least 6 (at least 1/week), ready months in 2-3 months — X Peat moss – only holds water, no nutrients, only recommended • Passive = pile up and for extremely sandy soils let nature do the work, ready in 2-3 years Don’t waste your money! Will not fix your problems!!!

Composting Composting

– YES: Vegetable scraps, fruit peels, eggshells, lawn clippings, yard debris, leaves, straw, manure – NO: meat/scraps, pet waste, perennial Bins are weeds/weed seed, helpful diseased plants but not – Finished product is Some wood ashes okay but required! typically 1/3 original too much raises pH – volume! sprinkle thin layers

9 3/14/18

What about Topsoil? Incorporate! • The soil on top - No standards • Organic matter breaks • Often contains weed seed and down quickly in warm, roots – screening can remove some of these humid climates • May contain disease spores, • Till into soil each year insects, chemical residues • A couple of inches of topsoil • 2”-3” layer, mix in 6”-8” deep does not provide adequate – NOT sand, peat moss, rooting depth! vermiculite or potting soil! • Creates perched water table – Gypsum/Landplaster, aka “Clay • Not the answer to soil Buster” does not help! problems!

Grow Your Own Compost! Seeding Cover Crops Cover Crops – Are mown or sprayed • Till soil and rake level when mature and left • Scatter seed thickly on soil surface over soil surface Green Manures • Rake in lightly – Are turned into the soil • Water Both are seeded directly into open garden spaces

Cover Crops Cover Crops and Green Manures

• Warm season cover crops: • Till in, mow, or spray a week or two – Sow mid-April – early Aug. after flowering begins – Cowpeas, soybeans, crowder peas = legume - add nitrogen • If leave too long, will set seed – Buckwheat = very quick, turn under in • When mowing – resprouting can 30-45 days be a problem • Cool season cover crops: • Can spray with glyphosate to kill – Sow Sept – Oct or Feb-March and plant directly into to crop – Hairy vetch, crimson clover = legumes debris 1 week later (no till) - add nitrogen – Rye, wheat often mixed in

Crimson clover (top) Buckwheat (bottom):

10 3/14/18

Another Option Amendments vs. Mulch

• Spread 2-10” layer of • Soil amendments- organic matter over top composted, suitable for • Wait 6 months to 1 year incorporation • Till under • May also be surface applied (top-dress) • ALSO: Maintain 3” mulch layer around plantings • Mulch- not decomposed; suitable for surface application only • If you can tell what it was, it’s not ready to Mulch improves soil over till in Too course to time (years) incorporate!

Vertical Mulching Plant Selection • Only way to alleviate • Some soils will always compaction around established stay moist, plant trees and shrubs moisture tolerant plants: • Very labor intensive but effective – River Birch • Drill 3”-4” wide holes, 18”-2’ – Bald Cypress deep throughout the root zone – Willow Oak (ideally at least every 2’) – Clethra • Fill with 50/50 mix of pea gravel – Hardy hibiscus and compost – can also add – Joe Pye Weed slow release fertilizer Soil Auger Siberian Iris, Virginia Sweetspire and Seashore Mallow all thrive in heavy to wet soils

Soil Chemical Properties Forests • Adapted species • Soil pH • Density matches the • Soil nutrient levels carrying capacity of the land • Fertilizers • Nutrients are recycled – • Soil testing leaves fall and rot • Soils are not compacted – amazing microbe activity! Address these issues AFTER soil physical properties are improved!

Why do the forests thrive For every live plant, how without fertilization? many plants didn’t make it?

11 3/14/18

Hydrangeas flower pink Soil pH in basic soils • Measure of how acidic or alkaline (basic) soil is N • Most NC soils typically e u acidic, > 5.3 t • 5.5 – 6.5 ideal for most More Acidic r More Alkaline plants (and microbes!) a l • Logarithmic scale And blue in 5 6 8 9 acidic 0 7 14 soils x10 x10

Logarithmic Scale: x 100 x 100

Ideal for most plants 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 How pH affects Acid Lovers: nutrient Prefer 5.0-5.5 availability • Azaleas • Width of horizontal bars represent how available • Dogwood nutrient is at different • Magnolia pH levels • Gardenia • 5.5 to 6.5 ideal for most • American Holly plants • Blueberries • Piedmont soils typically • Loropetalum 5.0 or lower • Virginia Sweetspire

• Centipedegrass Yellowing between the veins on new growth is a common symptom of high pH (iron deficiency)

Low Soil pH • pH below 5.0 too low for most plants, except blueberries! Must soil test to know how much too add • Submitting samples to soil test lab most accurate way to Ideal determine pH Range Lime 6.0 – Sulfur • Raise pH with lime – based on 6.5 soil test recommendation • Wood ashes – have 1/3 liming potential 0 7 14 Lime increases pH Sulfur lowers pH Lime Lifts! Sulfur Suppresses! Blueberries thrive in very acidic soils, pH 4.0-5.5

12 3/14/18

Raising pH Nutrients and Fertilizers • Raise with lime based on soil test results • Dolomitic lime also supplies magnesium Is Fertilizer Plant Food? • Target range 5.5 – 6.5 for most plants, – No! – plants make their own especially vegetables food by photosynthesis • Must mix into the soil, takes 6 months to completely react What is fertilizer? • If must surface apply (lawns), do not – Concentrated source of the apply more than 50 lbs. per 1000 sq. ft. nutrients plants need to at a time – fall/winter best time to apply produce their own food

Only apply fast acting lime in areas where plant are Carnivorous plants have found an alternate not growing nutrient source: Insects!

How do plants take up the nutrients they need? How Do Roots Absorb the ROOTS! Nutrients in Fertilizers?

• Can roots ingest fertilizer pellets? • No – nutrients must be dissolved in water • Fertilizers need water to work • This is why liquid fertilizers work so fast! • During drought plants cannot take up nutrients Must have healthy root system to take up nutrients

Low Nutrients Low Nutrients • NC soils typically lack required nutrient • Adjust pH first!!! levels • Soil test to determine which nutrients • Compost adds some nutrients but not and how much is needed enough • When to apply: • Supplement with fertilizers based on • Lawns – after mid April soil test recommendations • Vegetables – when growing • Organic and time release fertilizers • Ornamentals – spring provide nutrients over extended time • Containers – spring and mid- summer Yellowing and dropping of lower leaves is a common sign of nitrogen deficiency

13 3/14/18

Over Fertilizers: Fertilization Nutrient Sources Synthetic • Burn plant roots and – Manmade tissues – More predictable, higher analysis • Pollute ground and – More likely to leach, burn surface waters Natural • Increase insect and – Often low analysis, slow to release disease problems – Condition the soil – feed microbes • Overly lush plants require – Expensive if only source of more water; more frequent nutrients pruning/mowing – Do not release well in cold weather

Fertilizers Fertilizers • Time release fertilizers (e.g. • 10-10-10 and other granular Osmocote) = slowly release fertilizers nutrients over 2-6 months • Dissolve in water – excess leaches • Organic fertilizers naturally slow • Apply only small amounts at a time, reapply as release – nutrients not readily needed – easy to over do it! available in cold weather; feed • Specialty fertilizers microbes • Fertilizer spikes – not good! Need to spread fertilizer across root zone, not concentrate • Liquid fertilizers (Miracle Grow, • Rose, Tomato, ect. Fertilizer – just a marketing Compost tea) = fast food, quick ploy boost but no sustained feeding

18-18-21

What the numbers mean: Nitrogen 10-5-15 N Number on the bag represent % of: • Promotes green, leafy growth • Most limiting nutrient N P K – Most common deficiency • Most forms easily leach from Nitrogen Phosphorus Potassium/Potash soil - Pollute surface and New growth Roots, Flowers Flavor and groundwater and Fruits Hardiness – Not enough? Stunted growth, yellow leaves – older leaves For a 100 pound bag of fertilizer: first 10 – 5 – 15 = 10 lbs. N + 5 lbs. P + 15 lbs. K + 70 lbs. filler

14 3/14/18

Nitrogen Phosphorous 10-5-15 P • Promotes root growth, flower, • Too much burns plants fruit and seed production • Too much increases pest problems • Held tightly by soil – leaching – Especially aphids, scale, and rare mealybug • Causes pollution when soil • Too much reduces erodes, P attached to soil particles vegetable yields • Needs to be incorporated – Especially in beans, tomatoes, cucumbers, squash, peppers • Frequently fertilized soils probably have too much

Phosphorous Potassium 10-5-15 K Not Enough? – Reduced growth • Plant health tonic! – Plants dark green – Increases drought tolerance, disease resistance and – Purple or reddish color to improves winter hardiness older leaves Not taken up as well in cold or • Improves flavor in melons wet soils and tomatoes – Deficiency symptoms in • Can leach winter usually due to cold • Sometimes called potash weather rather than lack of • Visible deficiency symptoms nutrient in soil rarely seen though levels often low 18-18-21

Other Nutrients Miracle Grow All Purpose Plant Food • Calcium, magnesium, sulfur – occasionally need to supplement 24-8-16 » Epsom Salts: Magnesium sulfate • Lots of N! Plenty of K! • Micronutrients: iron, manganese, • Quick release, high analysis copper, zinc, molybdenum, boron, • Quick boost of growth chlorine, sodium – very rarely • No sustained feeding supplement • Easy to over feed Natural alternatives: fish emulsion, If pH is correct, these are compost tea rarely an issue Blossom End Rot is caused by calcium deficiency due to low pH, or more commonly, uneven watering

15 3/14/18

Espoma Plant-tone Osmocote 5-3-3 Indoor/Outdoor • Low analysis, some of everything, general feeding 3-4 month release • Slow release – organic 14-14-14 • Sustained feeding, good for • Balanced, time release microbes • Will release faster under warm • Not a ‘quick fix’ moist conditions (summer!) • 20 lbs./1000 sq. ft. = 1 lb. of • Takes 2-3 weeks for nutrients to nitrogen (60 cups) begin releasing • More expensive but worth it! • More expensive but worth it

Scott’s Southern Turf Builder Soil Sampling • 32-0-10 • Lots of N – new growth, no P, some K • Some of N in slow release form • Sustained feeding but too much N! • 3 lb. per 1000 sq.ft. = 6 cups

What Soil Sampling Can Why Soil Sample? and Can Not Tell You • ONLY accurate way of knowing what nutrients your soil needs Can Can Not • Find out pH (how acidic or basic – Nutrients your soil – Why your plant died, your soil is) and if changes need to needs to support unless nutrient or salt be made healthy growth related • Do it yourself kits are extremely – Soil pH, if lime is – If diseases are present inaccurate! needed or not in the soil – If nutrient levels are – Does not directly tell you too high (heavy how to amend your soil metals)

16 3/14/18

Soil Sampling in NC Soil Sampling • Send samples to NC Dept. of Agriculture Soil • Results are only as good as the Testing Lab in Raleigh sample! • No direct charge April – November; peak • Can be done anytime of the year season fee $4/box December-March • Plan ahead: want to send samples off and get results BEFORE beginning • Funded through fertilizer tax project • Results posted online – turnaround time • Wait 6-8 weeks after applying fertilizer or lime depends on time of year • Sample established areas every 2-4 years

Areas of Unique Use: How to Soil Sample Sample Different Areas Separately Start with clean equipment • Different – Stainless steel soil probe, hand plants/crops shovel, shovel • Changes in • Not brass, bronze or galvanized plant health – Clean plastic bucket • Obvious Decide where to sample changes in soil – Divide landscape into areas type (color, of unique use texture, topography) • 5-10 random samples from each area

Packaging Soil Samples How to Take Soil Samples • Boxes and forms available • Avoid thatch or mulch from any Extension office • Take a ‘slice’ of soil • Fill box to ‘fill’ level • Turf: 4” deep • Soil can be moist but not so • Landscape beds, wet it dissolves the box! vegetables: 6” deep • Do NOT put soil in plastic • Mix subsamples bag! together to make one • Do NOT tape box shut composite sample for each unique area

17 3/14/18

Soil Sample Forms Questions? • Fill in contact information (ink) Contact Information: • Make up sample ID # – Letters or numbers • Colby Griffin – Something you will remember (veg, flower, shrub, etc) – Franklin Horticulture Extension Agent • 919-496-3344 • Crop codes listed on back of sheet • [email protected] – Lawn and garden codes will give recommendations in lbs. per 1000 sq. ft. • Access results online: – http://www.ncagr.gov/agronomi/pals/

Next Week: Growing Veggies & Herbs

• Tuesday, March 13, 2018

Learn the basics of of year-round vegetable gardening and appropriate planting times.

18